This invention relates to a process for taking soil samples, wherein a core sample is taken from the ground which is to be analysed, and a section of the soil is removed from the core for subsequent analysis or other after-treatment. The invention also relates to a device for the performance of this process.
In order to enable optimization of the yield of harvests within the agricultural industry, it is normal current practice to determine the soil's content of additives, such as fertilizers, by taking a number of soil samples from over a field and then to analyse them. Using the result of the analysis, it is possible to determine the type and quantity of additive to be put into the soil in order to improve the harvest yield. At the same time, the costs of fertilization and other soil treatments is reduced, as is also environmental damage, since no excess of additive is put into the soil. Sampling is normally carried out along at least one sampling line over the field, whereby, using a drill steel, screw conveyor or the like, core samples are extracted from a number of points, for example 20, along the sampling line, and, from the core samples extracted in this way, a required sample volume is removed from a number of points corresponding to various soil depths.
The results of sampling and the subsequent analysis are naturally dependent on the precision in the sampling process, i.e. the same volumes being taken at the same levels along the whole of the sampling line. To date, however, removing samples from the core has been carried out manually, which has not led to satisfactory reproducibility of the sampling process and has also resulted in a number of drawbacks in other respects. Manual removal of a required, suitable volume, for example about 50 cm.sup.3, of sample has been performed by employing a tool to remove scrapings from the various levels of the core sample, which method, besides the disadvantage of the sampling process being time-consuming, has not provided precision in the sampling process. Thus the volume of sample scrapings has varied considerably, due to the difficulty of estimating the correct volume and because accompanying lumps of earth, stones, etc., have increased the volume to an indeterminable extent. Neither has it been possible to define exactly the levels on which the samples have been removed. In order to reduce handling time, removal of samples has had to be performed at the same time as moving the drilling equipment between the drilling points in the field, although this is further detrimental to accuracy, since the work has had to be performed at the same time as the equipment has been moving over the uneven surface of the field. A further disadvantage is that the residue of the core sample, after sample extraction, has had to be removed from the drill steel before the next drilling begins. This manual removal of the remains of the previous core sample is also time-consuming and laborious.
The main object of the invention is therefore to provide a process and device for taking of core samples, wherein these disadvantages are eliminated, so that it is possible for the rate of sampling to be substantially increased and precision improved, whereby the reliability of the test result obtained is improved considerably. These objects are achieved because the process and the device of the invention have been provided with the characteristics specified in the following patent claims .